Traces of a controversial herbicide have been found in Cheerios, Quaker Oats oatmeal, and other breakfast foods that could increase the risk of cancer, according to a group of environmental researchers. The Environmental Working Group said it tested 45 samples of breakfast foods made from oats grown in fields sprayed with the herbicide and found elevated levels of the weed killer glyphosate in 31 of them.

“There are levels above what we could consider safe in very popular breakfast foods,” said Alexis Temkin, the group’s toxicologist. Scott Partridge, a vice president at Monsanto—the company that developed the chemical—said hundreds of studies validated the safety of glyphosate and called the Environmental Working Group an activist group. “They have an agenda,” he said. “They are fear-mongering. They distort science.” The World Health Organization has called glyphosate a “probable carcinogen” and authorities in California list it as a chemical “known to the state to cause cancer.” Read more at The New York Times.